Address #2543:

Added constraint to limit use of attributes of the elementRef element

Author: sydb

P5/Source/Specs/elementRef.xml

@@ -10,6 +10,18 @@
     <memberOf key="model.contentPart"/>
   </classes>
   <content><empty/></content>
+  <constraintSpec ident="only_sensible_attrs" scheme="schematron">
+    <constraint>
+      <sch:pattern>
+        <sch:rule context="tei:elementRef[ parent::schemaSpec | parent::specGrp ]">
+          <sch:report test="@minOccurs | @maxOccurs" role="error">An element reference is not repeatable when part of a schema specification (and thus this &lt;elementRef> should not have @minOccurs or @maxOccurs).</sch:report>
+        </sch:rule>
+        <sch:rule context="tei:content//tei:elementRef">
+          <sch:report test="@source" role="error">An element reference within a content model must refer to a locally defined element specification (and thus this &lt;elementRef> should not have @source).</sch:report>
+        </sch:rule>
+      </sch:pattern>
+    </constraint>
+  </constraintSpec>
   <attList>
     <attDef ident="key" usage="req">
       <desc versionDate="2010-05-11" xml:lang="en">the identifier used for the required element within the
@@ -40,4 +52,4 @@
   <listRef>
     <ptr target="#TDmodules"/>
   </listRef>
-</elementSpec>
+</elementSpec>